Langenbucher Achim, Szentmáry Nóra, Cayless Alan, Al Karam Muntadher, Seiler Theo G, Wendelstein Jascha
Department of Experimental Ophthalmology, Saarland University, Homburg/Saar, Germany.
Dr. Rolf M. Schwiete Center for Limbal Stem Cell and Aniridia Research, Saarland University, Homburg/Saar, Germany.
PLoS One. 2025 Jul 18;20(7):e0327863. doi: 10.1371/journal.pone.0327863. eCollection 2025.
The purpose of this study was to investigate the repeatability of optical coherence tomography in measuring radius of curvature (ROC) and asphericity (Q) of corneal epithelium, stroma and endothelium in a large patient cohort.
In this retrospective non-randomized cross sectional single-center study we evaluated a dataset containing 600 anterior segment optical coherence tomography measurements from 200 eyes (3 repeat measurements each) taken prior to cataract surgery. Measurements were exported containing height map data for the epithelium, stroma and endothelium surface. Model surfaces (floating sphere in a 3 (BFS3) and 6 mm zone (BFS6) and conic surface in a 3 (Conoid3) and 6 mm zone (Conoid6)) were fitted using nonlinear iterative optimization minimizing the height difference between measurement and model. The mean (MEAN) and standard deviations (SD) for each sequence of measurements were derived and analyzed.
MEAN ROC for epithelium was 7.68/7.72/7.67/7.67 mm with BFS3/BFS6/Conoid3/Conoid6 and Q was -0.16/-0.19 with Conoid3/Conoid6. Corresponding values for stroma were 7.62/7.64/7.55/7.58 mm and -0.38/-0.24, and for endothelium they were 6.43/6.49/6.40/6.37 mm and -0.29/-0.33. Variations of the 3 repeat measurement ranged between 7-19/18-31/21-32 micron for epithelium/stroma/endothelium, and variation in Q was 0.14/0.20/0.14 with Conoid3 and 0.03/0.05/0.06 with Conoid6.
Fitting floating sphere or conoid model surfaces to the map data seems to be a very robust and reliable method for extracting ROC and asphericity from all data within a region of interest. For extraction of asphericity, the 6 mm zone should be used due to fewer variations.
本研究旨在调查光学相干断层扫描在测量大量患者队列中角膜上皮、基质和内皮的曲率半径（ROC）和非球面性（Q）方面的可重复性。
在这项回顾性非随机横断面单中心研究中，我们评估了一个数据集，该数据集包含白内障手术前从200只眼睛（每只眼睛进行3次重复测量）获取的600次眼前节光学相干断层扫描测量数据。导出的测量数据包含上皮、基质和内皮表面的高度图数据。使用非线性迭代优化拟合模型表面（3毫米（BFS3）和6毫米区域（BFS6）中的浮动球体以及3毫米（Conoid3）和6毫米区域（Conoid6）中的圆锥面），以最小化测量值与模型之间的高度差。得出并分析每个测量序列的平均值（MEAN）和标准差（SD）。
上皮的平均曲率半径（ROC）在BFS3/BFS6/Conoid3/Conoid6模型下分别为7.68/7.72/7.67/7.67毫米，在Conoid3/Conoid6模型下Q值为-0.16/-0.19。基质的相应值分别为7.62/7.64/7.55/7.58毫米和-0.38/-0.24，内皮的相应值分别为6.43/6.49/6.40/6.37毫米和-0.29/-0.33。上皮/基质/内皮的3次重复测量的变化范围在7 - 19/18 - 31/21 - 32微米之间，在Conoid3模型下Q值的变化为0.14/0.20/0.14，在Conoid6模型下为0.03/0.05/0.06。
将浮动球体或圆锥面模型表面拟合到地图数据似乎是一种非常稳健且可靠的方法，可从感兴趣区域内的所有数据中提取曲率半径和非球面性。对于非球面性的提取，由于变化较少，应使用6毫米区域。
